This invention relates in general to golf clubs and, more particularly, to golf clubs having weight inserts.
The swing weight of a golf club can be thought of as the ratio of the head weight to the grip weight measured at a consistent point of reference, typically 14 inches from the butt end of the club. Swing weights were, at one time, measured in ounces up to as much as 28 ounces, or more. Today, swing weight is most commonly measured on an arbitrary alphabetical scale from “A” to “G”, with “A” swing weighted clubs having relatively lower head weight to grip weight ratio and “G” swing weighted clubs having the highest ratio of head weight to grip weight. For a matched set of clubs, the swing weight should be consistent throughout the set for optimum performance (e.g., “D3” for a set of medium swing weighted men's clubs).
Because the swing weight of any particular club is a function of the shaft weight, club head weight, and grip weight, as well as manufacturing tolerances in the weight of all of these, clubs are advantageously swing weighted to the customer's specifications after final assembly. Ordinarily, this is accomplished by attaching a small balance weight to the exterior of the club, usually in a pocket formed in the outside wall of the club for this purpose.
Golf clubs come in many different styles and model designations all of which must be swing weighted at some point during their manufacture. In many cases, the club's model designation is imprinted on the balance weight so that it is visible once the balance weight is installed. Using an imprinted balance weight allows for ready identification of the model designation of the particular golf club. As can be readily determined from the foregoing, in order for a manufacturer to be able to swing weight each of its models across the full range of swing weights, it must maintain a separate inventory of swing weights imprinted for each model of club. Some economy of scale can be achieved by manufacturing the balance weights for each model of club so that they are all the same size and shape. The mass is then varied by varying the density (e.g., by using a tungsten-loaded thermoplastic in which the tungsten density is varied). This way a single mold can be used for all of the balance weights for a single club model. This does not, however, solve the inventory problem engendered by the necessity of having available a complete array of balance weights imprinted with markings for each club model.
One model of prior art iron-type club head 100, as shown in FIGS. 10 and 11, incorporated a two-piece weight 102 disposed in the back face 104 of the club head 100. The club head 100 included a hosel 106 for receiving a golf shaft (not shown) and a cavity 108 for receiving the weight 102. It will be understood that the weight 102 consists of a weight member 110 and a weight cover 112 that is locked in place over the weight member 110 by utilizing clips 114 on the weight cover 112 that snap into grooves 116 in the weight member 110.